Suspension damper with remotely-operable valve

ABSTRACT

A vehicle damper comprising a cylinder and a piston; a working fluid within the cylinder; a reservoir in fluid communication with the working fluid to receive working fluid from the cylinder in a compression stroke; and a remotely-operable valve, the valve operable to permit and restrict flow of the working fluid between the cylinder and the reservoir.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation application of and claims thebenefit of co-pending U.S. patent application Ser. No. 13/189,216, filedJul. 22, 2011, entitled, “SUSPENSION DAMPER WITH REMOTELY-OPERABLEVALVE”, by John Marking having Attorney Docket No. FOXF/0049USP1,assigned to the assignee of the present application, which isincorporated herein in its entirety by reference thereto.

The Ser. No. 13/189,216 application claims benefit of U.S. provisionalpatent application Ser. No. 61/366,871 (Atty. Dkt. No. FOXF/0049USL),filed Jul. 22, 2010, and U.S. provisional patent application Ser. No.61/381,906 (Atty. Dkt. No. FOXF/0051 USL), filed Sep. 10, 2010, each ofwhich is herein incorporated by reference.

The Ser. No. 13/189,216 application is also a continuation-in-part ofU.S. patent application Ser. No. 13/010,697 (Atty. Dkt. No.FOXF/0043USP1), filed Jan. 20, 2011 and is now Issued U.S. Pat. No.8,857,580, which claims benefit of U.S. provisional patent applicationSer. No. 61/296,826 (Atty. Dkt. No. FOXF/0043USL), filed Jan. 20, 2010.U.S. patent application Ser. No. 13/010,697 (Atty. Dkt. No.FOXF/0043USP1) is a continuation-in-part of U.S. patent application Ser.No. 12/684,072 (Atty. Dkt. No. FOXF/0032US), filed Jan. 7, 2010, nowabandoned, which claims benefit of U.S. provisional patent applicationNo. 61/143,152 (Atty. Dkt. No. FOXF/0032USL), filed Jan. 7, 2009. Eachof the aforementioned related patent applications is herein incorporatedby reference.

The Ser. No. 13/189,216 application is also a continuation-in-part ofco-pending U.S. patent application Ser. No. 12/684,072 (Atty. Dkt. No.FOXF/0032US), filed Jan. 7, 2010, which claims benefit of U.S.provisional patent application No. 61/143,152 (Atty. Dkt. No.FOXF/0032USL), filed Jan. 7, 2009. The Ser. No. 13/189,216 applicationis also a continuation-in-part of U.S. patent application Ser. No.13/175,244 (Atty. Dkt. No. FOXF/0047USP1), filed Jul. 1, 2011 and nowIssued U.S. Pat. No. 8,627,932, which claims benefit of U.S. provisionalpatent application No. 61/361,127, filed Jul. 2, 2010. Each of theaforementioned related patent applications is herein incorporated byreference.

BACKGROUND

1. Field of the Invention

Embodiments of the invention generally relate to a damper assembly for avehicle. More specifically, certain embodiments relate to aremotely-operated valve used in conjunction with a vehicle damper.

Vehicle suspension systems typically include a spring component orcomponents and a dampening component or components. Typically,mechanical springs, like helical springs, are used with some type ofviscous fluid-based dampening mechanism and the two are mountedfunctionally in parallel. In some instances features of the damper orspring are user-adjustable. What is needed is an improved method andapparatus for adjusting dampening characteristics, including remoteadjustment.

2. Summary of the Invention

The invention includes a vehicle damper comprising a cylinder and apiston; a working fluid within the cylinder; a reservoir in fluidcommunication with the working fluid to receive working fluid from thecylinder in a compression stroke; and a valve, the valve operable topermit and restrict flow of the working fluid between the cylinder andthe reservoir. In another embodiment, a pressurizable portion of areservoir adjacent a floating piston has an adjustable pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features can be understoodin detail, a more particular description may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a section view showing a suspension damping unit with areservoir.

FIGS. 2A and 2B are section views of the reservoir showing valves of avalve assembly in various positions during a compression stroke of thedamper.

FIGS. 3A and 3B are section views of the reservoir showing valves of avalve assembly in various positions during a rebound stroke of thedamper.

FIG. 4 is a section view of a damper in a compression stroke.

FIG. 5 is a section view of the damper of FIG. 4 in a rebound stroke.

FIG. 6 is a section view of a damper in a compression stroke.

FIG. 7 is a section view of the damper of FIG. 6 in a rebound stroke.

FIG. 8 is a schematic diagram showing a control arrangement for aremotely-operated valve.

FIG. 9 is a schematic diagram showing another control arrangement for aremotely-operated valve.

DETAILED DESCRIPTION

As used herein, the terms “down,” “up,” “downward,” “upward,” “lower,”“upper” and other directional references are relative and are used forreference only. FIG. 1 is a section view of a suspension damper 100. Thedamper 100 includes a cylinder portion 102 with a rod 107 and a piston105. In one embodiment, fluid meters from one side of the piston 105 tothe other side by passing through flow paths 110, 112 formed in thepiston 105. In the embodiment shown, shims 115, 116 are used topartially obstruct flow paths 110, 112 through the piston 105 in twodirections. By selecting shims having certain desired stiffnesscharacteristics, the dampening effects caused by the piston 105 can beincreased or decreased and dampening rates can be different between thecompression and rebound strokes of the piston 105. For example, shims115 are configured to meter rebound flow from the rebound portion 103 ofthe cylinder 102 to the compression portion 104 of the cylinder 102(shown as arrow 110). Shims 116, on the other hand, are configured tometer compression flow from the compression portion 104 of the cylinder102 to the rebound portion 103 (shown as arrow 112). In FIG. 1, thepiston is moving in a compression stroke (as shown by directional arrow117) with the rod 107 and piston 105 moving further into the compressionportion 104 and causing fluid to flow from a compression to a reboundside of the cylinder portion 102 via flow path 112. Note that pistonapertures (not shown) may be included in planes other than those shown(e.g. other than apertures used by paths 110 and 112) and further thatsuch apertures may, or may not, be subject to the shims 115, 116 asshown (because for example, the shims 115, 116 may be clover-shaped orhave some other non-circular shape). In one embodiment, the piston 105is solid and all damping flow must traverse a flow bypass (e.g. annularspace 150 between cylinder 102 and inner cylinder 151) and/orcommunicate with a reservoir.

In the embodiment of FIG. 1, the damper 100 includes an annular bypassformed between a wall of cylinder portion 102 and an inner wall 151having a slightly smaller diameter that the cylinder wall. In thismanner an annular space 150 is provided between the walls. In oneembodiment, at least one port 153 on the compression side of thecylinder and another port 154 on the rebound side permit working fluidto pass between the compression and rebound sides without moving throughthe shimmed paths provided by the piston 105. The bypass feature isutilized so long as the piston is between the two ports in either thecompression or rebound strokes.

The lower portion of the rod 107 is supplied with a bushing set 109 forconnecting to a portion of a vehicle wheel suspension linkage. An upperportion of the cylinder 102 may be supplied with an eyelet 108 to bemounted to another portion of the vehicle, such as the frame, that movesindependently of the first part. A spring member (not shown) is usuallymounted to act between the same portions of the vehicle as the damper.As the rod 107 and piston 105 move into cylinder 102 (duringcompression), the damping fluid slows the movement of the two portionsof the vehicle relative to each other due, at least in part, to theincompressible fluid moving through the shimmed paths provided in thepiston 105 and/or through the metered bypass. As the rod 107 and piston105 move out of the cylinder 102 (during extension or “rebound”) fluidmeters again through shimmed paths and the flow rate and correspondingrebound rate is controlled, at least in part, by the shims 115.

A reservoir 125 is in fluid communication with the damper cylinder 102for receiving and supplying damping fluid as the piston rod 107 moves inand out of the cylinder 102, thereby variably displacing damping fluid.The reservoir 125 includes a cylinder portion 128 in fluid communicationwith the compression portion 104 of the damper cylinder 102 via fluidconduit 129 which houses a fluid path between the components. Thereservoir 125 also includes a floating piston 130 with a volume of gasin a gas portion 131 on a backside (“blind end” side) of it, the gasbeing compressible as a fluid portion 132 of the reservoir cylinder 128fills with damping fluid due to movement of the damper rod 107 into thedamper cylinder 102. The pressure of gas in portion 131 can be adjustedwith compressed air introduced through gas valve 133 located at a lowerend of the reservoir cylinder 128. Certain features of reservoir-typedampers are shown and described in U.S. Pat. No. 7,374,028, which isincorporated herein, in its entirety, by reference. In one embodimentthe damper includes an in-line reservoir (e.g. floating piston and gascharge) rather than a remote reservoir as shown in FIG. 1. Theprinciples disclosed herein are equally applicable in either case.

In one embodiment, the damping characteristics of the damper 100 arealtered by at least one valve that regulates flow between thecompression chamber 104 and the fluid portion 132 of the reservoir 125.In the particular embodiment shown in FIG. 1, a reservoir valve assembly200 includes two valves 210, 220, each of which permits or preventsfluid flow into the reservoir fluid portion 132. The valves 210, 220 areshown in more detail in FIGS. 2A, B and 3A, B. FIGS. 2A and 2B aresection views of the reservoir 125 showing valves of the valve assembly200 in various positions during a compression stroke of the damper 100.FIGS. 3A and 3B are section views of the reservoir 125 showing valves ofthe valve assembly 200 in various positions during a rebound stroke ofthe damper 100.

As shown in the Figures, the reservoir valve assembly 200 is threadedlyattached at an upper end of the cylinder portion 128 of the reservoir125 and serves to seal the fluid portion 132. Valve 210 includes apathway leading into the fluid portion 132 of the reservoir, the pathwayincluding shims 212 functionally like those (115, 116) used in damperpiston 105 and designed to offer predetermined resistance to fluid flowpassing into the reservoir 125. Another set of shims 213 meter the flowof fluid out of the fluid portion 132 of the reservoir 125 during arebound stroke of the damper (FIGS. 3A, B). The flow of fluid into andthrough valve 210 in a compression stroke is shown by arrow 211. Asshown, the flow of fluid has un-seated shims 212 to permit the flow offluid into the fluid portion 132.

Another valve in the valve assembly 200 is a remotely-operable valve 220and includes a movable plunger 222 that is seatable on a seat 225. InFIG. 2A the valve 220 is open with a fluid path therethrough shown byarrow 221. While the Figure shows both valves open and fluid flowtraveling through both, it will be understood that depending upon thedesign of the system, including the selection of shims, valve 210 mightremain closed and fluid might flow only through open valve 220 (or viceversa). In FIG. 2B remotely-operable valve 220 is shown in a closedposition with the plunger 222 seated upon seat 225. In the embodimentshown, the valve 220 is shifted between an open and closed position by asolenoid 223 located above the valve and capable of receiving anelectrical signal and causing the mechanical movement of the plunger222. In one embodiment, the solenoid 223 operates in a manner thatpartially closes or partially opens the valve 220, therefore permittingor restricting flow without completely opening or closing the valve(e.g. as in an infinitely variable throttle operating between absoluteopen and absolute closed positions).

In one embodiment, the solenoid-operated valve 220 is normally open (asshown in FIG. 2A) with working or damping fluid permitted to flowthrough both valves 210, 220 of reservoir valve assembly 200. In theearly portion of the compression stroke, additional fluid may alsobypass the shims of piston 105 due to the annular bypass 150 with itsports 153, 154 (FIG. 1). The foregoing configuration describes a“compliant” damping mode with reduced dampening which is suitable for“plush” shock absorption but which may also allow a so-equipped vehicleto pitch or roll during braking or cornering respectively. As such,compliant damping is sometimes preferable but there are times when amore rigid damping mode is appropriate. In one embodiment, thenormally-open solenoid valve 220 may be, at the user's discretion,partially or completely closed as it appears in FIG. 2B, to increase adamping rate of the damper 100.

In some instances, it may be desirable to increase the damping rate whenmoving a vehicle from off-road to on highway use. Off-road use oftenrequires a high degree of compliance to absorb shocks imparted by thewidely varying terrain. On highway use, particularly with long wheeltravel vehicles, often requires more rigid shock absorption to allow auser to maintain control of a vehicle at higher speeds. This may beespecially true during cornering or braking.

In other instances, it is desirable to control/change dampeningcharacteristics in a rebound stroke of a damper. FIGS. 3A and B show theoperation of the damper 100 with working fluid traveling through thevalves 210, 220 of the assembly 200 in a rebound stroke. In FIG. 3A,both valves are open to the flow of return fluid. As shown, a fluid path216 is created through shims 213 of valve 210 and another path 217through the solenoid-operated valve 220 which is shown in an openposition, thereby reducing dampening effects and essentially permittingthe shock absorber to retract faster than would otherwise be possible.Such a setting is important in an instance where terrain is encounteredthat results in a sudden “drop” of the ground away from a wheel orwheels of the vehicle. FIG. 3B illustrates the same damper reservoir ina rebound stroke with the remotely-operable valve 220 in a closedposition, thereby adding additional dampening to the rebounding piston105.

One embodiment comprises a four wheeled vehicle having solenoidvalve-equipped shock absorbers at each (of four) wheel. The solenoidvalve 220 (which may be mechanically, pneumatically, or hydraulicallyoperated instead of solenoid operated) of each of the front shockabsorbers may be electrically connected with a linear, motion activatedswitch (such as that which operates an automotive brake light) that isactivated in conjunction with the vehicle brake pedal. When the brakepedal is depressed beyond a certain distance, corresponding usually toharder braking and hence potential for vehicle nose dive, the electricswitch connects a power supply to the normally open solenoid in each ofthe front shocks, thereby closing the valve in those shocks. As such,the front shocks become more rigid during hard braking. Other mechanismsmay be used to trigger the shocks such as accelerometers (e.g.,tri-axial) for sensing pitch and roll of the vehicle and activating, viaa microprocessor, the appropriate solenoid valves for optimum vehiclecontrol.

In one embodiment, a vehicle steering column includes right turn andleft turn limit switches such that a hard turn in either directionactivates (e.g. closes valve 220) the solenoid on the shocks oppositethat direction (for example a hard right turn would cause more rigidshocks on the vehicle left side). Again, accelerometers in conjunctionwith a microprocessor and a switched power supply may perform thesolenoid activation function by sensing the actual g-force associatedwith the turn (or braking; or throttle acceleration for the rear shockactivation) and triggering the appropriate solenoid(s) at a presetthreshold g-force.

In one embodiment, a pressure intensifier damper arrangement may belocated within the fluid path of the remotely-operable valves 220 suchthat the solenoid valve controls flow through that auxiliary damperwhich is then additive with the valve assembly 200. In one embodimentthe valve assembly 200 comprises a pressure intensifier (such asdescribed in U.S. Pat. No. 7,374,028, which is incorporated, entirely,herein by reference). In one embodiment one or both of the valves 210,220 comprise standard shim-type dampers. In one embodiment one or bothof the valves 210, 220 include an adjustable needle for low speed bleed.In one embodiment a blow off (e.g. checking poppet-type or shim) isincluded in one of the flow paths associated with the valves 210, 220.

Other embodiments are illustrated in FIGS. 4-7. For convenience, similarcomponents are labeled with the same numbers as components in previousembodiments. FIG. 4 is a section view of a damper 100 in a compressionstroke. Damping fluid is moved between compression chamber 363 andrebound chamber 365 via compression line 385, reservoir 125, and reboundline 386. The damper 100 includes a main cylinder 102 having a piston105 and shaft 107. In the case of the embodiment of FIG. 4, the pistonis solid and fluid is moved in each direction in both the compressionand rebound strokes of the damper. In another embodiment, the pistoncould include shims to meter fluid between the compression 363 andrebound 365 sides of the cylinder 102. Movement of the piston 105 intothe compression portion 363 is shown by directional arrow 117. Thecylinder also includes a bypass structure formed by an annular area 300between the outer wall 102 of the cylinder and an inner wall 101. A port154 leading from the annular area 300 to the rebound portion 365 of thechamber permits fluid flow into the rebound portion from the reservoiras will be explained. In one embodiment, the reservoir 125 is equippedwith a cylinder portion 128 housing a fluid portion 132 and apresurizable portion 131 separated by a floating piston 130. A valveassembly 220 enclosed in the reservoir housing operates to meter fluidinto and out of the reservoir 125.

Still considering FIG. 4, damping fluid is moved by solid piston 105 outof compression chamber 363 along the compression feed flow path 370 andinto fluid portion 132 of reservoir 125 via compression line 385, anannulus 380 and a port 381. Simultaneously, the pressure in reboundchamber 365 decreases as solid piston 105 moves in compression. Dampingfluid is correspondingly forced through the shims 115 of the valveassembly 200 and along the compression return flow path 371 to therebound portion 365 (which includes travel through rebound line 386,internal annulus 300, and port 154).

As the compression stroke progresses, the volume of the shaft 107incurring into the rebound/compression chamber 365/363 is accommodatedby movement of floating piston 130 in the reservoir 125 and associatedcompression of pressurizable portion 131. As pressure in portion 131increases, so does damping force of the shock absorber as increasedpressure is communicated to the damping fluid by movement of thefloating piston 130 (the damping fluid increases in pressure and affectschange in the pressure of, in one embodiment, a gas in portion 131).Increased damping fluid pressure acts against the piston area of thesolid piston 105, thereby increasing the force on the shock absorbernecessary cause compression of the shock absorber. In other words theshock absorber increasingly resists compression as it is compressed.

Referring to FIG. 5, an illustration of a rebound stroke, the shaft 107is moving out of the chambers 365, 363 as shown by directional arrow118. As illustrated, fluid flow directions are generally reversed fromthose shown in the compression stroke of FIG. 4. In particular, fluidexits the reservoir 125 along a path 372 that utilizes annular space 380and port 381. The exiting fluid 372 returns to the main dampeningcylinder 102 via annular area 300 and port 154 that leads to the reboundside 365 of the chamber. Rebound fluid enters the reservoir 125 via path373 and passes through shims 116 in valve assembly 200 where it ismetered.

In one embodiment, portion 131 of the chamber 128 comprises acompressible fluid such as a gas. In one embodiment an initial staticpressure of the gas is set between 150 and 250 psi. The pressurizableportion 131 is in fluid communication with a connection member 330 andan adjustable pressure source (not shown but noted by “201”). Theresistance of the shock absorber's increasing compression can be alteredas desired by adjusting the pressure using the adjustable pressuresource 201. If the source pressure is decreased, the shock absorber willbe relatively easier to compress and if the source pressure isincreased, the shock absorber will be more resistant to compression.

The source pressure can be increased for example, when a shockabsorber-equipped vehicle is operated on relatively smooth surface suchas a paved road and stiffness is more useful for good handling thancompliance. Conversely, if a so-equipped vehicle is operated off-road,compliant travel may be more desirable and the source pressure would becorrespondingly decreased. It is noteworthy that absent any adjustmentof the source pressure, the increasing resistance of the damper based oncompression of portion 131 is dependent primarily on the position of theshock in its travel (e.g. position dependent characteristic). As stated,the position/rigidity function associated with portion 131 and thedamping fluid pressure can be selectively altered and tailored byadjusting a pressure of the adjustable pressure source 201.

In one embodiment, the source pressure is adjustable by an operator of avehicle. For example, an on board source of compressed air can be usedto add pressurized gas to portion 131 in varying amounts either by aswitch in the vehicle compartment or as will be explained, in anautomated fashion based upon vehicle or terrain conditions. Similarly,pressure can be removed from portion 131 as needed.

FIGS. 6 and 7 illustrate a shock absorber that is similar to the shockabsorber of FIGS. 4 and 5 in some respects and similar to theembodiments of FIGS. 1 through 3 in other respects. In the embodiment ofFIGS. 6 and 7, however, the valve assembly 200 includes aremotely-operable valve 220 in addition to shims 115, 116 in order topermit additional and more responsive dampening control. For example, inFIG. 6 the compression flow 370 travels out of chamber 363 through line385 and into reservoir 125. Upon entering reservoir 125, the compressionflow path 370 is divided into two separate paths 370A, 370B, either orboth of which can be used to control dampening. Path 370A travelsthrough shims 116, like the shims of the other embodiments. Path 370Bhowever, travels through a remotely-operable valve 220 consisting of aplunger 222 and seat 225. Valve 220 is shown in an open positionpermitting fluid flow therethrough and in doing so, providing a bypassaround the dampening effects of the shims 116. Return fluid travelsalong a path 371 from fluid portion 132 through port 381, annular area380 and on to the rebound portion 365 of main dampening chamber 102, viareturn line 386.

FIG. 7 illustrates the operation of the damper of FIG. 6 in a reboundstroke. As piston 105 retracts (in direction shown by arrow 118), fluidfrom the rebound portion 365 of the main cylinder 102 utilizes port 154and annular area 300 to exit cylinder along a path 373. As the reboundfluid enters the reservoir, it utilizes annular area 380 and port 381 toenter fluid portion 132. From portion 132, the exiting fluid flow isdivided into two paths 372A and 372B. Path 372A takes the fluid throughshims 115 and path 372 B takes part of the fluid throughremotely-operable valve 220. As in the case of the compression stroke,the remotely-operable valve 220, in its open position as shown, reducesrebound dampening by providing a bypass around shims 115. While valve220 is shown in FIGS. 6 and 7 in a fully open position, it will beunderstood that the valve could be closed or could assume any number ofpartially-open positions depending upon the requirements of a vehicleand/or terrain and an operator's needs. In one embodiment, the valveassembly 200 is configured with a boost type position sensitive valve asshown and described in U.S. patent application Ser. No. 12/509,258 whichis entirely incorporated herein by reference. In one embodiment thedamping shims of the damping piston are selectively adjustable. In oneembodiment the shims of the damping piston are fixed.

As in other embodiments, the remotely-operable valve 220 may be solenoidoperated (as illustrated in FIGS. 6 and 7 with solenoid 223) orhydraulically operated or pneumatically operated or operated by anyother suitable motive mechanism. The valve may be operated remotely by aswitch or potentiometer located in the cockpit of a vehicle or attachedto appropriate operational parts of a vehicle for timely activation(e.g. brake pedal) or may be operated in response to input from amicroprocessor (e.g. calculating desired settings based on vehicleacceleration sensor data) or any suitable combination of activationmeans. In like manner, a controller for the adjustable pressure source(or for both the source and the valve) may be cockpit mounted and may bemanually adjustable or microprocessor controlled or both or selectivelyeither.

It may be desirable to increase the damping rate when moving a vehiclefrom off-road to on highway use. Off-road use often requires a highdegree of compliance to absorb shocks imparted by the widely varyingterrain. On highway use, particularly with long wheel travel vehicles,often requires more rigid shock absorption to allow a user to maintaincontrol of a vehicle at higher speeds. This may be especially trueduring cornering or braking

One embodiment comprises a four wheeled vehicle having solenoid valveequipped shock absorbers at each (of four) wheel. The solenoid valve(which in one embodiment is cable operated instead of solenoid operated)of each of the front shock absorbers may be electrically connected witha linear switch (such as that which operates an automotive brake light)that is activated in conjunction with the vehicle brake pedal. When thebrake pedal is depressed beyond a certain distance, correspondingusually to harder braking and hence potential for vehicle nose dive, theelectric switch connects a power supply to the normally open solenoid ineach of the front shocks thereby closing the paths 8SA in those shocks.As such the front shocks become more rigid during hard braking. Othermechanisms may be used to trigger the shocks such as accelerometers(e.g. tri-axial) for sensing pitch and roll of the vehicle andactivating, via a microprocessor, the appropriate solenoid valves foroptimum vehicle control.

In one embodiment, a vehicle steering column includes right turn andleft turn limit switches such that a hard turn in either directionactivates (e.g. closes path 8SA) the solenoid on the shocks oppositethat direction (for example a hard right turn would cause more rigidshocks on the vehicle left side). Again, accelerometers in conjunctionwith a microprocessor and a switched power supply may perform thesolenoid activation function by sensing the actual g-force associatedwith the turn (or braking; or throttle acceleration for the rear shockactivation) and triggering the appropriate solenoid(s) at a presetthreshold g-force.

In one embodiment, a pressure intensifier damper arrangement may belocated within the fluid path such that the solenoid-controlled valvecontrols flow through that auxiliary damper which is then additive withthe damper mechanism of the damping piston. In one embodiment the dampermechanism of the damping piston comprises a pressure intensifier. In oneembodiment one or both of the dampers comprise standard shim typedampers. In one embodiment one or both of the dampers include anadjustable needle for low speed bleed. In one embodiment a blow off(e.g. checking poppet type or shim) is included in one of the flow pathsor in a third parallel flow path.

FIG. 8 is a schematic diagram showing a control arrangement 400 for aremotely-operated valve, like valve 220 described herein or in oneembodiment, the pressure source 201. As illustrated, a signal line 416runs from a switch 415 to a solenoid 223 along an electricallyconductive line 416. Thereafter, the solenoid 223 converts electricalenergy into mechanical movement (identified by item 405) and shifts aplunger of the valve 220, thereby opening or closing the valve orcausing the plunger to assume some predetermined position in-between.While FIG. 8 is simplified and involves control of a single bypass valve220, it will be understood that any number of valves could be operatedsimultaneously or separately depending upon needs in a vehicularsuspension system. Additional switches could permit individual operationof separate remotely-operable valves 220.

As discussed, a remotely-operable valve 220 or a remotely operatedpressure source 201 like the one described above is particularly usefulwith an on-/off-road vehicle. These vehicles can have as more than 20″of shock absorber travel to permit them to negotiate rough, uneventerrain at speed with usable shock absorbing function. In off-roadapplications, compliant dampening is necessary as the vehicle relies onits long travel suspension when encountering often large off-roadobstacles. Operating a vehicle with very compliant, long travelsuspension on a smooth road at higher speeds can be problematic due tothe springiness/sponginess of the suspension and corresponding vehiclehandling problems associated with that (e.g. turning roll, brakingpitch). Such compliance can cause reduced handling characteristics andeven loss of control. Such control issues can be pronounced whencornering at high speed as a compliant, long travel vehicle may tend toroll excessively. Similarly, such a vehicle may pitch and yawexcessively during braking and acceleration. With the remotely-operatedbypass dampening and “lock out” described herein, dampeningcharacteristics of a shock absorber can be completely changed from acompliantly dampened “springy” arrangement to a highly dampened and“stiffer” (or fully locked out) system ideal for higher speeds on asmooth road. In one embodiment, where compression flow through thepiston 105 is completely blocked, closure of the valve 220 can result insubstantial “lock out” of the suspension (the suspension is renderedessentially rigid except for the movement of fluid through shimmed valve210). In one embodiment, where some compression flow is allowed throughthe piston 105 or the annular bypass 150, closure of the valve 220results in a stiffer but still functional compression damper.

In addition to, or in lieu of, the simple, switch operated remotearrangement of FIG. 8, the remotely-operable valve 220 can be operatedautomatically based upon one or more driving conditions. FIG. 9 shows aschematic diagram of a remote control system 500 based upon any or allof vehicle speed, damper rod speed, and damper rod position. Oneembodiment of the arrangement of FIG. 9 is designed to automaticallyincrease dampening in a shock absorber in the event a damper rod reachesa certain velocity in its travel towards the bottom end of a damper at apredetermined speed of the vehicle. In one embodiment, the system 500adds dampening (and control) in the event of rapid operation (e.g. highrod velocity) of the damper to avoid a bottoming out of the damper rodas well as a loss of control that can accompany rapid compression of ashock absorber with a relative long amount of travel. In one embodiment,the system 500 adds dampening (e.g. closes or throttles down the bypass)in the event that the rod velocity in compression is relatively low butthe rod progresses past a certain point in the travel. Suchconfiguration aids in stabilizing the vehicle against excessive low-ratesuspension movement events such as cornering roll, braking andacceleration yaw and pitch and “g-out.”

FIG. 9 illustrates, for example, a system 500 including three variables:rod speed, rod position and vehicle speed. Any or all of the variablesshown may be considered by logic unit 502 in controlling the solenoidsof valves 220 or control of a remotely operated pressure source. Anyother suitable vehicle operation variable may be used in addition to orin lieu of the variables 515, 505, 510 such as, for example, piston rodcompression strain, eyelet strain, vehicle mounted accelerometer (ortilt/inclinometer) data or any other suitable vehicle or componentperformance data. In one embodiment, piston 105's position withincylinder 102 is determined using an accelerometer to sense modalresonance of cylinder 102. Such resonance will change depending on theposition of the piston 105 and an on-board processor (computer) iscalibrated to correlate resonance with axial position. In oneembodiment, a suitable proximity sensor or linear coil transducer orother electro-magnetic transducer is incorporated in the dampeningcylinder 102 to provide a sensor to monitor the position and/or speed ofthe piston 105 (and suitable magnetic tag) with respect to the cylinder102. In one embodiment, the magnetic transducer includes a waveguide anda magnet, such as a doughnut (toroidal) magnet that is joined to thecylinder and oriented such that the magnetic field generated by themagnet passes through the piston rod 107 and the waveguide. Electricpulses are applied to the waveguide from a pulse generator that providesa stream of electric pulses, each of which is also provided to a signalprocessing circuit for timing purposes. When the electric pulse isapplied to the waveguide, a magnetic field is formed surrounding thewaveguide. Interaction of this field with the magnetic field from themagnet causes a torsional strain wave pulse to be launched in thewaveguide in both directions away from the magnet. A coil assembly andsensing tape is joined to the waveguide. The strain wave causes adynamic effect in the permeability of the sensing tape which is biasedwith a permanent magnetic field by the magnet. The dynamic effect in themagnetic field of the coil assembly due to the strain wave pulse,results in an output signal from the coil assembly that is provided tothe signal processing circuit along signal lines. By comparing the timeof application of a particular electric pulse and a time of return of asonic torsional strain wave pulse back along the waveguide, the signalprocessing circuit can calculate a distance of the magnet from the coilassembly or the relative velocity between the waveguide and the magnet.The signal processing circuit provides an output signal, either digitalor analog, proportional to the calculated distance and/or velocity. Atransducer-operated arrangement for measuring rod speed and velocity isdescribed in U.S. Pat. No. 5,952,823 and that patent is incorporated byreference herein in its entirety.

While a transducer assembly located at the damper measures rod speed andlocation, a separate wheel speed transducer for sensing the rotationalspeed of a wheel about an axle includes housing fixed to the axle andcontaining therein, for example, two permanent magnets. In oneembodiment, the magnets are arranged such that an elongated pole piececommonly abuts first surfaces of each of the magnets, such surfacesbeing of like polarity. Two inductive coils having flux-conductive coresaxially passing therethrough abut each of the magnets on second surfacesthereof, the second surfaces of the magnets again being of like polaritywith respect to each other and of opposite polarity with respect to thefirst surfaces. Wheel speed transducers are described in U.S. Pat. No.3,986,118 which is incorporated herein by reference in its entirety.

In one embodiment, as illustrated in FIG. 9, the logic unit 502 withuser-definable settings receives inputs from the rod speed 510 andlocation 505 transducers as well as the wheel speed transducer 515. Thelogic unit 502 is user-programmable and depending on the needs of theoperator, the unit records the variables and then if certain criteriaare met, the logic circuit sends its own signal to the bypass to eitherclose or open (or optionally throttle) the remotely-operable valve 220.Thereafter, the condition of the bypass valve is relayed back to thelogic unit 502.

In one embodiment, the logic shown in FIG. 9 assumes a single damper butthe logic circuit is usable with any number of dampers or groups ofdampers. For instance, the dampers on one side of the vehicle can beacted upon while the vehicles other dampers remain unaffected.

While the examples illustrated relate to manual operation and automatedoperation based upon specific parameters, the remotely-operated valve220 (with or without valve 210 in valve assembly 200) or the remoteoperation of pressure source 201 can be used in a variety of ways withmany different driving and road variables. In one example, the valve 220is controlled based upon vehicle speed in conjunction with the angularlocation of the vehicle's steering wheel. In this manner, by sensing thesteering wheel turn severity (angle of rotation), additional dampeningcan be applied to one damper or one set of dampers on one side of thevehicle (suitable for example to mitigate cornering roll) in the eventof a sharp turn at a relatively high speed. In another example, atransducer, such as an accelerometer, measures other aspects of thevehicle's suspension system, like axle force and/or moments applied tovarious parts of the vehicle, like steering tie rods, and directs changeto the bypass valve positioning in response thereto. In another example,the bypass can be controlled at least in part by a pressure transducermeasuring pressure in a vehicle tire and adding dampeningcharacteristics to some or all of the wheels in the event of, forexample, an increased or decreased pressure reading. In one embodiment,the damper bypass or bypasses are controlled in response to brakingpressure (as measured, for example, by a brake pedal sensor or brakefluid pressure sensor or accelerometer). In still another example, aparameter might include a gyroscopic mechanism that monitors vehicletrajectory and identifies a “spin-out” or other loss of controlcondition and adds and/or reduces dampening to some or all of thevehicle's dampers in the event of a loss of control to help the operatorof the vehicle to regain control.

While the foregoing is directed to embodiments of the invention, otherand further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A vehicle damper comprising: a cylinder and a piston; a working fluidwithin the cylinder; a reservoir in fluid communication with the workingfluid, the reservoir operable to receive working fluid from the cylinderin a compression stroke; and a remotely-operable valve, the valveoperable to permit and restrict flow of the working fluid between thecylinder and the reservoir.